Wheeled support frames are well known. For example, devices to accommodate infants, such as bassinets, cribs, cradles and the like are often mounted upon wheeled supports. In some applications, it is advantageous to provide a wheeled support designed to enable the wheel assemblies to be selectively moved between retracted and extended positions. One such structure is described in U.S. Pat. No. 5,636,853, granted Jun. 10, 1997. A factor in the ease of use of these structures is the ease in which the rollers are moved between retracted and extended positions.
The device disclosed in U.S. Pat. No. 5,636,853 provides retractable wheel supports on an infant bed support enabling it to roll on a suitable surface with the rollers extended, or rock on arcuate members when the rollers are retracted. Such a device provides both rocking and non-rocking modes for an infant bed. However, the mechanism used for releasing, retracting and extending each roller requires an awkward and difficult manual actuation which requires two (2) different manual operations to be performed substantially simultaneously. It is desirable to provide a mechanism which allows a support frame to adjust between stationary and rolling modes easily with a minimum of effort.